The debt-growth nexus and debt sustainability in Nigeria: Are there reasons to be concerned?

This study examined the threshold effect of debt on economic growth in Nigeria, with a view to investigating debt sustainability levels in the country. The analysis included yearly data from 1981 to 2021. To achieve its objectives, the study used two-regime threshold ARDL regression approaches. Findings reveal that the optimal thresholds for total debt as a ratio of GDP (TDB/GDP), GNI (TDB/GNI), total revenue (TDB/REV), and exports of goods and services (TDB/EXP) are 46.1%, 54.5%, 355.3%, and 24.9%, respectively. Findings also indicate that debt ratios below the threshold levels have a significant positive impact on economic growth. This is true for all the debt ratios, except debt-to-export ratio. However, debt ratios above the threshold levels have a negative and significant effect on Nigeria’s economic growth. Furthermore, findings reveal that only the level of domestic debt is sustainable over the long and short run, whereas external debt and total debt are only sustainable over the long run. When expressed as ratios of GDP and GNI, evidence indicates that Nigeria’s debt is not sustainable by all the five measures of debt adopted in the study, both in the short run and in the long run while total debt to revenue ratio is only sustainable only in the long run. The paper adequately explores the implications of these findings and offers relevant policy recommendations.